1. Field of the Invention
The present invention relates to a shrinkage control material used for various kinds of molding, a door window glass run channel or the like for automobiles, and bead material for window frames or the like for buildings, and to a elastomeric molding using the same.
2. Description of the Related Art
Various kinds of molding and window door glass run channel for automobiles, window frame beads for buildings or the like are generally formed of rubber or resin by means of extrusion.
In the extrusion products of rubber or resin as mentioned above, in order to prevent the rubber or resin from shrinking to deform due to temperature variation during molding or use, a resilient metal wire is used to bury. In burying the wire, it is general that the metal wire is passed through a coater to coat an adhesive around an outer periphery thereof. Thereafter, while introducing the adhesive coated metal wire into an extruder, around the outer periphery thereof rubber or resin is extruded.
However, in the method like this, there is a problem that the adhesive coater is necessary to be disposed before the extruder to result in a complicated process control.
To this problem, a shrinkage control material or a reinforcement material has been developed in which, on a surface of a metal wire, melt-bonding varnish is coated and baked in advance to dispose a melt-bonding layer.
According to the shrinkage control material, due to heat during extrusion of the rubber or resin, the hot-melt layer is once melted, thereafter together with the rubber or resin being cooled to solidify into one body. Accordingly, the adhesive coater is not required to be disposed ahead of the extruder.
For the melt-bonding varnish to be coated on the surface of the metal wire, so far the melt-bonding varnish based on polyester resin is generally used.
However, the polyester resin based varnish is a little weaker in adhesion to the rubber than to the resin. Accordingly, there is a problem that the shrinkage control material using the polyester resin based melt-bonding varnish can not exhibit an expected shrinkage prevention effect in a rubber molding.
Accordingly, a shrinkage control material that is excellent in adhesion to the rubber and can exhibit a sufficient shrinkage prevention effect to the rubber is desired to develop.